The batting material must be faced and at least as thick as the joists are wide so the batting is nearly flush with the top of the joists.
Do i need faced insulation between floors.
Unless you have an extra 10 000 and a big hearted desire to create jobs in the insulation industry it makes no sense to insulate between floors.
The floor does not belong in the building envelope.
Any time you use a faced insulation the paper needs to be facing toward the living space.
Sticking your vapor barriers and thermal resistance into places besides the exterior building shell can create odd interior dynamics.
Faced or the type with paper is typically used in first time applications such as in walls ceilings floors and in crawl spaces.
The main reason why you do not need insulation on the floors is simple.
So in an attic the paper faces downward and in a crawl space it faces upward.
Unfaced insulation the type without paper is what you would use if you are adding insulation to your attic or to place between floors when living space is above and below.
Floor insulation can sometimes reduce the room temperature below the dew point.
Floor insulation can hamper the dynamic of vapour barriers and thermal resistance.
The biggest concern that can happen due to floor insulation is mould.